Our long-term aim is to identify and characterize mechanisms by which genes are turned on and off during development of eucaryotic organisms. To this end, we have cloned a family of developmentally regulated genes from the nematode, c aenorhabditis elegans. Our preliminary data indicates that these genes probably code for the yolk proteins. They encode high molecular weight mRNAs which are abundantly produced in the adult hermaphrodite but not in larvae or in males. We will first identify the protein products of each gene and then will fully characterize the genes and the RNAs for which they code. We will determine the number of genes in the family and their degree of relatedness. Their approximate map location will be ascertained. A detailed restriction map of each gene will be prepared and used to determine the location of coding and non-coding regions as well as the ends of the genes. The size and abundance of the mRNAs encoded by each gene will be investigated. We will use in situ hybridization to study the timing and tissue specificity of expression of the genes and to investigate the possibility that the genes are hormonally regulated. An attempt will be made to use the clonal genes to identify and isolate proteins which control their expression. A search for variants of the yolk proteins in natural populations and for mutants altered in the control of their expression will be instituted. The cDNA bank from which these genes were originally cloned will be used to clone additional genes of interest from C. elegans. In particular, we hope to clone the gene for the muscle protein, paramyosin, to use in developing a system by which C. elegans mutants can be transformed to wild-type.